How much energy & money do LED lamps save?

Grade level: 4th – 5th grades

Skills: Multiplication

Related environmental issues: Energy conservation

The table below shows how much electricity each light bulb uses to light your room in 1 year.

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  1. Your house has 30 light fixtures.  How much electricity do you use during a year if you use a regular light bulb for each light fixture?
  2. How much electricity do you use during a year if you use an energy saving light bulb for each house’s light fixture?
  3. How much electricity can you save if you replace all of the 30 regular light bulbs with energy saving light bulbs?
  4. The average price of 1kwh-electricity in California was 21 cents in August 2018. How much money could your family save for electricity in a year if you replaced all of the 30 light bulbs with energy saving light bulbs in a year?

 

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Answer keys

  1. 200 x 30 = 6,000 (kWh)
  2. 30 x 30 = 900 (kWh)
  3. 6,000 – 900 = 5,100 (kWh)
  4. 5,100 x 21 = 107,100 (cents) = $ 1,071

 

SOLAR ENERGY IN THE US

Grade level: 3rd – 5th grades

Skills: Addition & Subtraction (Decimal numbers)

Related environmental issues: Energy /  Renewable Energy

The table below shows shows how much new solar power was installed the United States each year between 2008 and 2017. Solar power means electricity generated by solar panels.

1 Gigawatt = 100,000,000 kilowatts (With 1 gigawatt of solar power, we can power 190,000 homes!)

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1. Which year has the largest number?

2. What is the difference between the numbers of the years 2014 and 2015?

3. Is the amount of solar panels installed in 2011 more than those installed in 2009 and 2010 combined or less?

4. What is the difference between the largest number and the smallest number?

5. Which year has the number 4.4 larger than  0.38?

6. Which two numbers make the largest value when added?

Sources:

 

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Answer keys

  1. 2016
  2. 7.5 – 6.24 = 1.26
  3. More : 1.92 > (0.38 + 0.85)
  4. 15.13 – 0.3 = 14.83
  5. 2013
  6. 15.13 and 10.61